Abstract: A method and apparatus of compatibly and simultaneously transmitting and receiving an encoded signal with the normal visual and aural carrier of a television signal is disclosed. The encoded signal is used as a modulating signal to frequency modulate the visual carrier frequency signal prior to amplitude modulating the visual carrier frequency signal with a source of composite video signals. Normally, the introduction of additional sideband power even in the form of constant amplitude components will cause visual distortion to a received picture due to the normal Nyquist shaped bandpass characteristics of the intermediate frequency amplifier in the television receiver. This distortion is reduced or eliminated in several ways. The maximum allowable frequency modulation deviation can be limited so that the visual distortion is substantially reduced.